| 摘要 |
PURPOSE:To prevent an adjustment magnification from being shifted easily and naturally due to a vibration, etc., by providing a variable power ring turning lock means. CONSTITUTION:By turning a knob 94c in the screwing direction against a screw hole 94f, and setting a state that the tip of an external screw part 94d is pressed against the outside surface of a main lens barrel 91 to which a variable power ring 94 has been fitted externally, the variable power ring 94 is brought to a turning stop against the main lens barrel 91 and becomes a turning lock state. On the contrary, when the knob 94c is turned in the loosening direction, the tip of the male screw part 94d is separated from the outside surface of the main lens barrel 91 and the turning stop to the main lens barrel 91 of the variable power ring 94 is released, and by pinching the knob 94c, the variable power ring 94 can be brought to a turning operation against the main lens barrel 91. In such a way, even if a turning resistance of the variable power ring is set small, a magnification variation which is apt to occur therefore can be prevented.
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